Damper mechanism

ABSTRACT

A damper mechanism which includes a cylinder with a movable shaft therein with the shaft having a swingable valve on the outer surface. The end of the swingable valve will contact the cylinder when the shaft is rotated in one direction to form a nonreturn valve due to its association with a partitioning member having an oil passage to communicate chambers formed on opposite sides of the partitioning member. When the shaft is rotated in one direction with the valve moving toward the partitioning member, rotational movement of the shaft in that direction will be dampened by restricted movement of oil from one chamber to the other. When the shaft is rotated in the opposite direction, the valve moves away from the cylindrical surface thus enabling unrestricted rotational movement of the shaft in the opposite direction.

BACKGROUND OF THE INVENTION

1. Technical Field

This invention relates to a damper mechanism for generating an effect ofdamping impact by utilizing the pressure drag of a highly viscousfunctional oil.

2. Prior Art

A damper mechanism utilizing a functional oil as a damping medium asillustrated in illustrated in FIG. 5 of the accompanying drawings isalready known.

The damper mechanism of FIG. 5 comprises a cylinder a, a blade shaft bdisposed along the axis of the cylinder a, a blade c filled to the outerperipheral surface of the blade shaft b and designed to slidingly moveon the inner peripheral surface of the cylinder a, an upper stationarybearing (not shown) and a lower stationary bearing (not shown) forrotatably holding the blade shaft b, a stationary blade g arrangedoutside the blade c and a nonreturn valve i disposed in an oil passage hrunning through the stationary blade g, the inside space d of thecylinder a being divided into two chambers A, B by the blade c, both ofthe chambers A, B being filled with a functional oil e.

If a relatively large gap exists between the inner peripheral surface a'of the cylinder a and the blade c of a damper mechanism illustrated inFIG. 5, the functional oil e can leak through the gap at an enhancedrate to reduce the damping effect of the mechanism when the blade shaftb is rotated. If, on the other hand, no gap exists therebetween, theblade c becomes incapable of moving smoothly within the cylinder a.

For a damper of the above described type, therefore, there always arisesa requirement of reconciling the prevention of leakage of functional oile and the smooth movement of the blade c.

In order for the requirement to be met, the inner peripheral surface a'of the cylinder a, the blade shaft b, the blade c and other metallicparts of a conventional damper mechanism are subjected to precisionmachining and precision assembly so that the gap may be made as small aspossible.

Obviously such measures can, by turn, pose technical difficulties inmachining and assembly of metallic parts and components of the dampermechanism.

Additionally, a conventional damper mechanism as described above isaccompanied by the problem of poor durability due to the fact thatfriction inevitably occurs between the inner peripheral surface a' ofthe cylinder a and the blade c as the latter slidingly moves on theformer until they are abraded and no longer able to operate on a stablebasis.

An alternative measure that has been proposed for the prevention ofleakage of function oil e consists in providing the blade c with alining member f and a sealing member.

With such a proposed technique of using a lining member f and a sealingmember, the level of precision machining and assembly of metallic partsand components may apparently be reduced.

Such a technique, however, is accompanied by the problem of earlyabrasion of the lining member f and the sealing member at locationswhere they are held in contact with the inner peripheral surface a'particularly when the surface a' is coarsely finished.

Therefore, the proposed technique cannot satisfactorily provide aprolonged stability and an enhanced durability of a damper mechanismunder consideration.

An additional cost will be involved in the manufacture of a dampermechanism as illustrated in FIG. 5 when an oil passage h is boredthrough the stationary blade g of the cylinder a and a nonreturn valve iis arranged at the oil passage h.

SUMMARY OF THE INVENTION

In view of the above identified technological problems of existingdamper mechanisms, it is therefore an object of the present invention toprovide a damper mechanism that can be economically manufactured, stablyoperates for a prolonged period of time and has an excellent durability.

According to the invention, the above object is achieved by providing adamper mechanism comprising a cylinder, a movable shaft and a movablevalve, said movable valve being disposed along said movable shaft andswingable on the outer peripheral surface of said movable shaft, saidmovable shaft being inserted into said cylinder with said movable valveand rotatable relative to said cylinder, the front end of said movablevalve being disposed vis-a-vis the inner peripheral surface of saidcylinder and capable of detachably contacting said cylinder to form anonreturn valve realized by utilizing the movable valve and disposedbetween the inner peripheral surface of said cylinder and the outerperipheral surface of said movable shaft, a partitioning member beingdisposed between the inner peripheral surface of said cylinder and theouter peripheral surface of said movable shaft and longitudinallydisposed therebetween, the inner space of said cylinder being capable ofbeing divided by the nonreturn valve and the partitioning member into aplurality of chambers having volumes variable relative to each other andheld in communication with each other by way of an oil passage boredthrough the boundary of the chambers, said variable volume chambersbeing filled with functional oil.

Preferably, the movable valve is flap-shaped and swingably disposed onthe outer peripheral surface of the movable shaft by way of a valveholder.

Preferably, the partitioning member is constituted by a block-likepartitioning piece projecting from the inner peripheral surface of thecylinder toward the outer peripheral surface of the movable shaft.

The partitioning member may be rigidly fitted to the inner peripheralsurface of the cylinder or, alternatively, movably arranged between theinner peripheral surface of the cylinder and the outer peripheralsurface of the movable shaft.

When the partitioning member is movably arranged between the innerperipheral surface of the cylinder and the outer peripheral surface ofthe movable shaft, it may be so disposed in a guide groove formed on thecylinder wall as to be capable of being pushed toward the outerperipheral surface of the movable shaft and retracted toward the innerperipheral surface of the cylinder.

When a such positionally adjustable partitioning member is used, an oilpassage for keeping the variable volume chambers in communication witheach other may be formed between the front end of the partitioningmember and the outer peripheral surface of the movable shaft and thecross section of the oil passage may be variable.

When a positionally adjustable partitioning member is used, thecommunication between the inner peripheral surface of the cylinder andthe outer peripheral surface of the movable shaft may be totallydisconnected.

The oil passage connecting the variable volume chambers mayalternatively be formed in the partitioning member or the movable valve.

When the oil passage is formed in the partitioning member or the movablevalve, the partitioning member or the movable valve will be providedwith a through bore.

Alternatively, an oil passage may be formed in the partitioning memberand the movable valve at the same time.

When an oil passage is formed in the partitioning member and the movablevalve at the same time, the oil passage in the movable valve will have across section smaller than that of the oil passage in the partitioningmember.

Such an oil passage will normally be a narrow orifice.

Still alternatively, a plurality of combinations of a nonreturn valveand a partitioning member may be provided in the cylinder in a mannersame as or similar to the above described one.

When a plurality of combinations of a nonreturn valve and a partitioningmember are provided, the inner space of the cylinder is divided intofour or more than four variable volume chambers.

When external force is applied clockwise or counterclockwise to themovable shaft of a damper mechanism according to the invention to rotatethe movable shaft in the direction of the applied external force, themovable valve fitted to the movable shaft also rotates in the samedirection.

As described earlier, the movable valve is detachably contacting theinner peripheral surface of the cylinder to form a nonreturn valvewithin the cylinder.

The nonreturn valve principally constituted by the movable valve candivide each of the variable volume chambers in the cylinder and bedisplaced along the inner peripheral surface of the cylinder as themovable shaft is rotated.

Thus, as the movable shaft is rotated and consequently the nonreturnvalve is displaced in a manner as described above, the variable volumechambers in the cylinder changes their respective volumes relative toeach other so that the nonreturn valve is opened or closed as a functionof the flowability and pressure drag of the functional oil generated bythe changes in the volumes.

The opening or closing action of nonreturn valve may be best understoodby referring to a damper mechanism whose nonreturn valve is opened whenthe movable shaft is rotated counterclockwise and closed when themovable shaft is rotated clockwise.

With such a nonreturn valve, the movable valve which is a principalcomponent of the nonreturn valve is readily moved away from the innerperipheral surface of the cylinder to open the nonreturn valve under theresistance of the functional oil when the movable shaft is rotatedcounterclockwise because it is subjected to no external force trying tokeep it under a closed condition.

As the nonreturn valve is opened, the functional oil begins to flow fromone of the variable volume chambers into the other chamber. Therefore,under this condition, no damping effect is produced there and themovable shaft smoothly rotates counterclockwise.

If, now, the movable shaft is rotated clockwise, the movable valve whichis a principal component, of the nonreturn valve is readily moved towardthe inner peripheral surface of the cylinder until the former comes intocontact with the latter to close the nonreturn valve under theresistance of the functional oil.

As the nonreturn valve is closed, the flow of functional oil is blockedthere and, therefore, the volume of one of the variable volume chambersis gradually reduced if the movable shaft is rotated further clockwise.On the other hand, the other variable volume chamber is graduallyexpanded.

If there were no flow of functional oil under this condition, themovable shaft would stop rotating. Since, however, the functional oil inthe variable volume chamber having a reduced volume is allowed to flowthrough the orifice for passage of oil into the expanding variablevolume chamber, the movable shaft is made to slowly rotate as a functionof the flow rate of the functional oil.

Thus, a damper mechanism according to the invention produces a givendamping effect when the movable shaft is rotated clockwise.

It will be understood that a similar damping effect can be obtained whenthe cylinder is held stationary and only the movable shaft is made torotate and compress the functional oil contained in one of the variablevolume chamber or, conversely, when the movable shaft is held stationaryand only the movable shaft is made to rotate. It will also be understoodthat a similar effect can be achieved still alternatively, when thecylinder and the movable shaft are made to rotate in oppositedirections.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross sectional view of a preferred embodiment of dampermechanism of the present invention.

FIG. 2 is a longitudinal sectional view of the embodiment of FIG. 1 cutalong line A--A in FIG. 1.

FIG. 3 is a schematic perspective view of the partitioning member of theembodiment of FIG. 1.

FIG. 4 is a lateral elevation view of a swing system incorporating theembodiment of FIG. 1.

FIG. 5 is a cross sectional view of a conventional damper mechanism.

BEST MODE OF CARRYING OUT THE INVENTION

Now, the present invention will be described in greater detail byreferring to the accompanying drawings that illustrates a preferredembodiment of the invention.

Referring to FIGS. 1 through 3, 1 denotes a cylinder, 2 a movable shaft,3 a bearing, 4 a setscrew, 5 a bearing, 6 and 7 O-rings, 8 a valveholder, 9 a movable valve, 10 a functional oil, 11 a partitioningmember, 12 an adjust screw, 13 a guide groove, 14 a tapped hole, 15 anO-ring, 16 an oil passage, 17 an arm, 18 an angle adjust screw, 19 ametal holdfast, 31 and 32 variable volume chambers.

The cylinder 1 comprises a tapped section 1b disposed near an end of theinner peripheral surface and a tubular section 1a disposed close to theother end and provided with a closure 1d at the end and is combined witha circular lid 1c having a threaded outer peripheral surface which isheld in engagement with the tapped section 1b.

The closure 1d of the tubular section 1a is provided with a shaftbearing hole 1e, a circular groove 1g and a seal seat 1i while the lid1c is also provided with a shaft bearing hole 1f, a circular groove 1hand a seal seat 1j.

The tubular section 1a also has a guide groove 13 running on the innerperipheral surface 1k of its thick side wall and a tapped through bore14 that can bring the guide groove 13 into communication with the outerperipheral surface of the cylinder 1.

The movable shaft 2 comprises an inner shaft member 2a provided with asplined section 2b near an end thereof and a serrated section 2f nearthe other end and an outer shaft member 2c engaged with the splinedsection 2b on the outer peripheral surface of the inner shaft member 2a.

The cap-shaped bearing 3 fitted onto the outer peripheral surface of theinner shaft near the upper end thereof is held in engagement with thesplined section 2b and rigidly secured to the upper end of the innershaft 2a by means of the setscrew 4.

The cylindrical outer shaft 2c is provided on its outer peripheralsurface 2e with the valve holder 8 having an arcuately recessed holdingsection 8a.

The movable valve 9 has a flaplike shape and provided with a cylindricalshaft section 9a projecting downward from the bottom.

The shaft section 9a of the movable valve 9 is squeezed into the holdingsection 8a of the valve holder 8 and pivotally held there.

The partitioning member 11 has a blocklike shape as is illustrated inFIG. 3.

The partitioning member 11 is provided on the inside with a relativelywide engaging groove 11b running from an end of the member substantiallyto the middle and on the outside with a relatively narrow engaginggroove 11a which communicates with the relatively large engaging groove11b.

The adjust screw 12 which is driven into the partitioning member 11comprises a neck section 12a disposed near an end thereof and receivedin the engaging groove 11a and a head section 12b disposed at an end ofthe neck section 12a and received in the engaging groove 12b.

The above described components will be assembled to a damper mechanismtypically in a manner as described below.

In the first step of assembling operation, the lower end of the innershaft member 2a is introduced into the shaft bearing hole 1e of thetubular section 1a with the interposition of the bearing 5 and the lowerend of the outer shaft member 2c is received in the groove 1g of theseal seat 1i of the tubular section 1a with the interposition of theO-ring 6.

Now, the movable shaft 2 is set in position in the cylinder 1.

Thereafter, the shark section of the movable valve 9 is squeezed intothe holding section 8a of the valve holder 8.

The movable valve 9 pivotally filled onto the outer peripheral surfaceof the movable shaft 2 is now slidingly movable on the inner peripheralsurface of (the tubular section 1a of) the cylinder 1 to produce anonreturn valve 9d between the inner peripheral surface of the cylinderand the outer peripheral surface of the movable shaft.

Referring particularly to FIG. 1, when the movable shaft 2 is rotatedcounterclockwise (in the direction as indicated by arrow c) , thenonreturn valve 9d is released to open itself, whereas it is closed whenthe movable shaft 2 is rotated clockwise (in the direction as indicatedby arrow d).

In the second step, the adjust screw 12 which is holding the O-ring 15is driven into the tapped through bore 14 of the tubular section 1a.

Now, the neck section 12a and the head section 12b of the adjust screw12 which is held to the tubular section 1a project into the guide groove13.

Thereafter, when the partitioning member 11 is squeezed into the guidegroove 13 of the tubular section 1a, the engaging grooves 11a, 11b ofthe partitioning member 11 respectively come to be engaged with the necksection 12a and the head section 12b.

Thus, a partitioning section 11c is formed within the cylinder 1 by thepartitioning member 11.

The narrow oil passage 16 is now produced between the inner front end ofthe partitioning member 11 and the outer peripheral surface of the outershaft member 2c of the movable shaft 2 as the inner end of thepartitioning member 11 is brought close to the outer peripheral surfaceof the movable shaft 2.

The position of the partitioning member 11 can be adjusted to enlarge ornarrow the oil passage 16 by moving the member 11 in either direction ofthe arrow in FIG. 2 by means of the adjust screw 12.

Thus, the inner space of the cylinder 1 is divided into two variablevolume chambers 31, 32 by the nonreturn valve 9d and the partitioningsection 11c and the two variable volume chambers 31, 32 are held incommunication with each other by way of the oil passage 16.

The variable volume chambers 31, 32 are filled with functional oil inthis stage of assembling operation.

In the final stage of assembling operation, the lid 1c carrying theO-ring 7 on its seal seat 1j is fitted to the opening of the tubularsection 1a to airtightly seal the inner space of tile cylinder 11 by wayof the mutual engagement of the tapped section 1b and the correspondingthreaded section (not designated by a reference symbol).

Under this condition, a top portion of the inner shaft member 2a thatcarries the bearing 3 is squeezed into the shaft bearing hole 1f while atop portion of the outer shaft member 2c is squeezed into the groove 1hof the lid 1c.

The arm 17 is fitted to the outer periphery of (the tubular section 1aof) the cylinder 1 by means of the angle adjust screw 18 and the metalholdfast 19 is fitted to the serrated shaft section 2f of (the innershaft member 2a of) the movable shaft 2 projecting out of the (tubularsection 1a of) the cylinder 1.

All the components and members of a damper mechanism according to theinvention are made of metal and/or hard synthetic resin except thesealing members which are made of rubber or synthetic resin of a knowntype.

The functional oil 10 may be any viscous fluid (oil) or oily viscous andelastic fluid selected from silicon oil, grease and high molecularsubstances.

The above described embodiment of damper mechanism of the presentinvention may be modified in various ways.

A possible modification is that the partitioning member 11 is rigidlysecured to the inner peripheral surface 1k of the cylinder 1.

With such an arrangement, a through bore is bored through either themovable valve 9 or the partitioning member 11 and serves as an oilpassage 16.

Another modification is that both the movable valve 9 and thepartitioning member 11 are provided with an oil passages 16.

With such an arrangement, the oil passage through the movable valve 9has a cross section smaller than that of the oil passage through thepartitioning member 11.

Still another possible modification is that a plurality of combinationsof a nonreturn valve 9d and a partitioning section 11c are arranged in amanner same as or similar to that of arrangement of the above describedembodiment.

With such an arrangement, the inner space of the cylinder 1 is dividedinto four or more than four variable chambers.

FIG. 4 illustrates a swing lid (door) to which the embodiment of dampermechanism of the invention is applied.

In FIG. 4, an arm 22 is articulated at an end to a corresponding end ofanother arm 17 whose other end is rigidly secured to the cylinder of thedamper mechanism while the other end of the arm 22 is pivotallyconnected to a metal holdfast 23.

A cabinet 20 as illustrated in FIG. 4 is provided at an edge of itsopening 21 with a swing lid 25 which is anchored to the cabinet 20 bymeans of a hinge 24.

The metal holdfast 19 is rigidly secured to the inner surface of alateral wall of the cabinet 20 near the opening 21 by means of screws.The metal holdfast 23 is, on the other hand, rigidly secured to thelower surface of the swing lid 25 by means of screws.

Thus, the damper mechanism comprising the arms 17, 22 and othercomponents operates like an elbow disposed between a portion of alateral wall of the cabinet 20 near the opening of the cabinet 20 andthe swing lid 25.

If the swing lid 25 is turned from its closed position as indicated bysolid lines in FIG. 4 to an open position as indicated by phantom linesin FIG. 4, the cylinder 1 is rotated by means of the arms 17, 22 in adirection as shown by arrow b' relative to the movable shaft 2 which isrigidly secured to a lateral wall of the cabinet 20 near the opening 21by means of the metal holdfast 19.

As the cylinder 1 is rotated, the nonreturn valve 9d is opened to allowthe functional oil 10 contained in the variable volume chamber 32 tosmoothly flow into the other variable volume chamber 31 so that the lid25 is turned open without any substantial resistance.

If, then, the swing lid 25 of the cabinet 20 is turned back from theopen position as indicated by phantom lines to the closed position asindicated by solid lines in FIG. 4, the cylinder 1 is rotated in adirection as shown by arrow a' which is opposite to the direction shownby arrow b'.

As the cylinder 1 is rotated, the nonreturn valve 9d is closed and thevariable volume chamber 31 is compressed by the movable valve 9 whereasthe other variable volume chamber 32 is expanded to an equal extent.

Under this condition, since the functional oil 10 contained in thecompressed variable volume chamber 31 is partly fed to the expandedvariable volume chamber 32 by way of the oil passage 16 the movableshaft 2 is slowly rotated to softly close the lid 25.

The angular speed of the movable shaft 2 and that of the lid 25 aredetermined by the flow rate of functional oil running through the oilpassage 16.

Thus, the angular speed of the closing lid 25 can be appropriatelyselected by moving the inner front end of the partitioning member 11closer to or away from the outer peripheral surface of the movable shaft2 and therefore by adjusting the cross section of the oil passage 16.

A damper mechanism according to the invention and capable of exerting anabove described damping effect can advantageously find variousapplications where a component of a structure is rotated in two oppositedirections and the rotation of the component is natural in a givendirection whereas the rotation in the other direction need to becontrolled.

Industrial Applicability

As described above, a damper mechanism according to the invention has asimple configuration of comprising a movable shaft housed in a cylinderalong with a nonreturn valve, a partitioning member and an oil passageand the variable volume chambers formed within the cylinder andseparated by the nonreturn valve and the partitioning member are filledwith functional oil.

A damper mechanism according to the invention produces an effect ofdamping any rotary movement of the movable shaft when the movable shaftis rotated in a given direction.

Thus, it is only a movable valve which is a principal component of thenonreturn that is subjected to contact and friction with the innerperipheral surface of the cylinder while the damper mechanism isoperated, whereas any other components thereof are practically notsubjected to friction.

Moreover, the movable valve is subjected to contact with the innerperipheral surface of the cylinder only when the damper mechanismproduces a damping effect and, because the contact between the movablevalve and the cylinder is very soft and mild, either of them will not beabraded.

Additionally, since the movable valve operates as a blade for drivingfunctional oil to flow and as a nonreturn valve for blocking the flow offunctional oil, the overall number of components of such a dampermechanism is advantageously reduced.

Thus, a damper mechanism according to the invention can be economicallymanufactured, stably operates for a prolonged period of time and has anexcellent durability. Such a damper mechanism can advantageously findvarious applications where a damping effect is required.

What is claimed is:
 1. A damper mechanism comprising a cylinder having an inner peripheral surface, a movable shaft having an outer peripheral surface and a movable valve, said cylinder including an internal volume filled with functional oil, said movable valve being disposed along said movable shaft and swingable on the outer peripheral surface of said movable shaft for movement toward and away from the inner peripheral surface of said cylinder, said movable shaft being inserted into said cylinder with said movable valve and rotatable relative to said cylinder, a front end of said movable valve being disposed vis-a-vis the inner peripheral surface of said cylinder and contacting the inner peripheral surface of said cylinder to form a nonreturn valve disposed between the inner peripheral surface of said cylinder and the outer peripheral surface of movable shaft to dampen movement of the shaft when the shaft is rotated in one rotational direction, the front end of said movable valve being moved out of engagement with the inner peripheral surface of the cylinder to form a return valve to enable unrestricted movement of the shaft when the shaft is rotated in an opposite direction of rotation, a partitioning member disposed between the inner peripheral surface of said cylinder and the outer peripheral surface of said movable shaft and longitudinally disposed therebetween, an inner space of said cylinder being divided by the nonreturn valve and the partitioning member into a plurality of chambers having volumes variable relative to each other, said chambers being communicated with each other by an oil passage through a boundary of the chambers to control flow of functional oil between the chambers when the shaft is rotated in said one direction to dampen rotation of the shaft when the shaft is rotated in said one direction.
 2. A damper mechanism according to claim 1, wherein the inner space of the cylinder is divided into at least two variable volume chambers by at least one combination of a nonreturn valve and a partitioning member.
 3. A damper mechanism according to claim 1, wherein the movable valve is flap-shaped and swingably disposed on the outer peripheral surface of the movable shaft by way of a valve holder.
 4. A damper mechanism according to claim 1, wherein the partitioning member is constituted by a block-like partitioning piece projecting from the inner peripheral surface of the cylinder toward the outer peripheral surface of the movable shaft.
 5. A damper mechanism according to claim 4, wherein the partitioning member is so fitted to the inner peripheral surface of the cylinder as to be movable between the inner peripheral surface of the cylinder and the outer peripheral surface of the movable shaft.
 6. A damper mechanism according to claim 4, wherein said oil passage is formed between the front end of the partitioning member and the outer peripheral surface of the movable shaft to keep the variable volume chambers in communication with each other.
 7. A dampener for restricting rotational movement of a shaft in one direction and enabling unrestricted rotation of the shaft in an opposite direction, said dampener comprising a housing having an interior cylindrical surface, a rotatable shaft extending into said housing in spaced relation to the cylindrical surface, a valve member mounted on said shaft for movement toward and away from the interior cylindrical surface on the housing, a partitioning member mounted on the housing and extending toward the shaft and terminating in adjacent relation thereto, the interior of the housing being filled with a viscous fluid, said partitioning member being spaced from the valve member and dividing the space between the shaft and interior cylindrical surface on the housing into a pair of chambers which can vary in volume, said valve member being movable toward and into contact with the interior cylindrical surface on the housing during rotation of the shaft in one direction to move the valve member toward the partitioning member, said partitioning member including an oil passage restricting flow of viscous fluid past the partitioning member thereby dampening rotational movement of said shaft in said one direction, said valve member being moveable toward the shaft and out of contact with the interior cylindrical surface on the housing when the shaft is rotated in an opposite direction to enable unrestricted rotational movement of said shaft when the shaft is rotated in said opposite direction.
 8. The dampener as defined in claim 7 wherein said valve member is pivotally supported from said shaft for swinging movement about an axis parallel to a longitudinal axis of said shaft, said valve member including an outer end having a curved surface engageable with the interior cylindrical surface on the housing to form a nonreturn valve when the shaft is rotated in said one direction and being moved back toward the shaft by the viscous fluid when the shaft is rotated in the opposite direction.
 9. The dampener as defined in claim 7 wherein said oil passage is a space provided between the shaft and an inner end of said partitioning member. 